The deep-sea hatchetfish certainly meets that standard.

Difficulty of care: 5. The Marbled Hatchetfish is the best suited Hatchetfish to life in aquaria. Even though the Marbled Hatchet is the hardiest Hatchetfish, it is still not recommended for beginning aquariasts. is slightly hardier.

Unknown. Probably breeds in a similar fashion to the marbled hatchetfish, .

The Half-naked Hatchetfish, Argyropelecus hemigymnus, has been assessed as Least Concern. This species has a wide global distribution and is not known to face any major threats due to its deepwater nature. In addition there is no dorected commercial fishery due to its small size and the depths at which it is found. The population numbers are likely to be stable.

And that is not the hatchetfish's only optical trick.

Remarks: The Marbled Hatchetfish can leave the water and "fly" for up to 10 feet (3.05 m). I'm sorry to reference such an old question (I believe it was from2005?), but I have looked through the other WWM postings on hatchetfish and not found other references related to this issue. Iwasn't sure how serious Mr. Fenner was with this advice. (Ah,one of the dangers of online communication--not being able todistinguish a writer's nonverbal communication!)

IT KILLED THE HATCHETFISH. IT KILLED THE HATCHETFISH DEAD.

So, here is my question: While quarantining hatchet fish, is itwise to feed them antibiotic-laced food as a 'preemptive'measure, or is it best to wait and see if the fish are essentiallyhealthy? I am hesitant to give the fish antibiotics until I havereason to believe they really need them, but if the health ofwild-caught hatchets (in general) is that tenuous, I can understand theneed to treat them preemptively.

Getting hatchetfish to stay at the top 9/26/06Hello Crew


The deep sea hatchetfish gets its name from the distinct hatchet-like shape of its body. It is a member of the Sternoptychidae family of deep sea fishes. There are about 45 individual species of hatchetfish that vary in size from one to six inches. They are most well known for their extremely thin bodies which really do resemble the blade of a hatchet. They should not be confused with the freshwater hatchetfish commonly seen in home aquariums.The hatchetfishes are provided with a complex system of conspicuous light-producing spots. The species has one row of 12 very low down along each side of the deep forward part of the body; also, a second row higher up consisting of 6 in front of each pectoral fin, 2 along the base of the pectoral, 6 between pectoral and ventral fins, 4 between the ventral and the anal fins, 6 along the anal, and 4 very small ones between anal and tail fins. There is also one light-organ a little below and behind each eye, 2 on the lower part of the gill cover on each side and about 5 on the lower jaw on each side.
The hatchetfish has upward-oriented eyes that allow it to gauge the position of prey above it. Light-producing photophores are used in a defensive behavior called counter-lighting. Hatchetfish are abundant in the Caribbean and Gulf of Mexico. Image courtesy of Islands in the Stream 2001, NOAA/OER.Of the several species of hatchetfish that inhabit the ocean depths, the largest is Argyropelecus gigas, also known as the giant or large hatchetfish. This giant of the family grows to an impressive six inches (12 centimeters) in length. Most of the smaller hatchetfish species are covered in delicate silvery scales. Some species, including the giant hatchetfish can be brown or dark green in color. Hatchetfishes have large, tubular eyes that pointing upward. This enables them to search for food falling from the above. Because there is very little light at the great depths at which they are found, their eyes have become extremely sensitive to light and are good at distinguishing shadows against the extremely faint illumination from above.